Breathing assistance apparatus

ABSTRACT

A nasal cannula assembly is disclosed having a face mount part, in use resting against a user&#39;s face, which includes at least one nasal prong capable of being fitted into a person&#39;s nares. The cannula assembly also includes a manifold part, in fluid communication with the face mount part, having a single horizontal side gases entry. In particular, this cannula assembly is for supplying heated, humidified gases to a patient suffering from COPD. A tie or lanyard is disclosed for use with a breathing assistance apparatus such as a nasal cannula, face or nasal mask or tracheostomy connector. The tie or lanyard transfers the weight of the conduits supplying gases to the breathing assistance apparatus from the breathing assistance apparatus and distributes it onto the neck of the patient.

FIELD OF INVENTION

[0001] The present invention relates particularly, though not solely, tothe delivery of high flow humidified pressurised oxygen and/or air to apatient in need of respiratory support by way of a nasal cannula

SUMMARY OF THE PRIOR ART

[0002] Nasal cannula generally consist of entry tubing, either symmetricor single sided that lies across the upper lip. Protruding from thistubing are open ended prongs which extend into the nares of the patientto deliver oxygen. Nasal cannulae have the advantage of being morecomfortable and acceptable than a face mask to most patients. Theexisting market for nasal cannula is well serviced by devices suitablefor the delivery of gases in the 0 to 5 litre per minute range. Thesedevices are typically supplied by a double entry lumen of small diameter(2-3 mm range) that supplies both sides of the nasal cannula andprovides even airflow to each nasal prong. These devices work well forthe delivery of low humidity gas flows of between 0 to 5 litre perminute and have been well received by patients over the last 30 years.

[0003] Hudson Respiratory Care Incorporated manufactures a nasal cannulathat is disclosed in U.S. Pat. No. 2,868,199 that consists of a singleflow entry nasal cannula. This single flow entry has the advantage ofbeing unobtrusive, and more relevant to delivering humidity than a dualflow entry style of nasal cannula, simply due to the advantage of flowrates and surface area for heat loss. The single flow entry is on theleft side only, which causes the user difficulty in use if the flowsource is on the opposite side of the user requiring longer lengths oftubing and causing the tube to cross the body. The cannula itself ismanufactured as one part only, of PVC plastic. This product is notdesigned for delivering high flow or high humidity gases. The nasalprongs are less than 3 mm in diameter resulting in noise and highvelocity jetting of gas causing severe irritation at high flows. Thesecannulae are difficult to clean inside, are uncomfortable, and theprongs are too rigid for extended therapies.

[0004] U.S. Pat. No. 3,754,552 of Sandoz-Wander, Inc discloses a nasalcannula, having two nasal prongs, adapted for the intake of therapeuticgas from either the right or left side of the patient. Here the nasalcannula has a bore within it that feeds each prong. The bore is able toreceive a tube for supplying gases to the cannula in either end and inuse a plug is required to obstruct the unused end.

[0005] Innomed Technologies, Inc manufactures a nasal cannula devicecalled the NASALAIRE™. This nasal cannula is a dual flow entry stylecannula where two large tubes come from behind the ears, through thefield of vision to the upper lip. In this device air or oxygen travelsdown a wide bore conduit to the nasal cannula. The NASALAIRE™ creates aphysical seal between the nares and itself, and relies on the absence ofleaks around itself and the nares to deliver pressure supplied by acontinuous positive airway pressure (CPAP) blower to the airway of thewearer. The wearer is required to breathe in and out of the NASALAIRE™,thereby rebreathing some of the exhaled air from the lungs. TheNASALAIRE™ is not designed to deliver humidified gases to the patient,being unheated and without insulation of any type. The NASALAIRE™cannula is uncomfortable especially if a patient rests on the tube, aswould happen during sleep, and is also obtrusive.

[0006] The new application of high airflow extended therapies usingnasal cannulae generally result in the nasal cannula reachingtemperatures in excess of 35 degrees C. Usually cannulae are made fromsoft polymeric material (for example, silicone) that absorbs heat anddoes not breathe and therefore sweat is generated under the contactpoints with the skin. This heat in combination with the polymericmaterials waterproof properties results in sweat being trapped against apatient's skin and the patient has the sensation of overheating. Thetrapped sweat is uncomfortable and could lead to rashes.

[0007] Oxygen is generally supplied as a dry gas, but it is well knownin the art to either heat and/or humidify gases before delivering themfor breathing by a patient. In particular when delivering oxygen, or anoxygen air mixture, it has proven beneficial to humidify the gases firstIn WO 01/41854 of Vapotherm, Inc. a system is disclosed that allows thedelivery of humidified oxygen through a nasal cannula. This system usesa narrow bore conduit and nasal cannula with a high resistance to gasflows, thereby requiring the oxygen be of a high pressure. Air, as wellas oxygen, can also be passed down the conduit and nasal cannula and ittoo must be of a high pressure. This system allows the delivery of highflows of oxygen enriched air to the patient, but is limited in the flowsachievable due to the narrow bore of the cannula resulting in highresistance gas flow and excessive velocity and noise upon exiting thecannula. Furthermore, the narrowness of the nasal cannula in this systemallows the patient to easily expire gases from their nostrils as thereis a reasonable gap between the prongs and the patient's nares. Thuspositive airway pressure is not created and as such this cannula is notsuitable for the treatment of Obstructive Sleep Apnea (OSA).

[0008] In breathing circuits that supply respiratory gases to a patientby way of a patient interface, such as a nasal cannula, mask or trachealtube, it is common, to have a heated breathing circuit or tubedelivering heated and humidified gases to the patient, followed by ashort length of non-heated tube close to the patient. This unheated tubemay be a short unheated extension tube or catheter mount. The unheatedsection of tube is usually intended to be very flexible to reducetorsion or pulling on the patient interface, to allow the gases to coolslightly towards the dew point of the gas, and also to eliminate hotsurface temperatures near the patient. As this tube is unheated thetemperature of the tube walls are colder than the dew point temperatureof the gas, as a result the vapour in the gases passing near these wallswill begin to condense out. Over time a build up of condensate close tothe patient may lead to a build-up of bacteria which may causeinfection. Build up of condensation may also create noise, such asgurgling, which may wake a patient, and in extreme circumstances thefluid build up may cause drowning.

[0009] When providing humidified gases to a patient it is common to usea heated breathing circuit (tubing). This circuit is heavy and can dragand pull on the patient interface. This is more pronounced if thepatient is mobile and can be painful and/or dangerous if the patientinterface is invasive such as an endotracheal tube. It is common to usea short flexible tube between the heated circuit and patient interfaceto reduce any torque or twisting. In order to stop the weight pulling onthe patient interface, circuit hangers are occasionally used. This is alarge extendable metal arm to take the weight. It also has been known inthe art to clip part of the tubing to the patient's clothes orbedclothes. Both of these solutions have been found to be quiteunsuitable for mobile patients especially when sleeping and turning inbed.

[0010] With patient interfaces such as nasal cannulae the stability ofthe nasal prongs on the face is very important, as movement of theprongs within the nares can cause severe irritation. Current methodsemployed to retain a single entry nasal cannula on the face use a simpleelastic band of material around the back of the patients head This isprone to rotating the nasal cannula relative to the patient's headespecially when turning ones head on a pillow. This rotation causes theprongs move within the nares, irritating this sensitive area.

SUMMARY OF THE INVENTION

[0011] It is an object of the present invention to provide a breathingassistance apparatus which goes someway to overcoming the abovementioned disadvantages or which will at least provide the public auseful choice.

[0012] Accordingly in a first aspect the present invention consists in anasal cannula assembly adapted to deliver gases to a patient comprising:

[0013] a face mount part, including at least one nasal prong capable ofbeing fitted into at least one of said patient's nares,

[0014] a removable gases flow manifold part in use in fluidcommunication with said face mount part, said manifold part having asingle horizontal side gases entry, in use, in fluid communication withsaid transport means.

[0015] In a second aspect the present invention may broadly be said toconsist in a breathing assistance apparatus comprising:

[0016] a pressurised source of gases,

[0017] humidification means adapted to, in use, be in fluidcommunication with said source of gases and adapted to in use humidifysaid gases,

[0018] humidified gases transport means adapted to, in use, be in fluidcommunication with said humidification means and adapted to in useconvey said humidified gases,

[0019] heating means disposed within said transport means and adapted toin use heat said gases as they pass through said transport means, and

[0020] nasal cannula, adapted to deliver said humidified gases to saidpatient, said nasal cannula comprising a face mount part, including atleast one nasal prong capable of being fitted into at least one of saidpatient's nares, a removable gases flow manifold part in use in fluidcommunication with said face mount part, said manifold part having asingle horizontal side gases entry, in use, in fluid communication withsaid transport means.

[0021] The invention consists in the forgoing and also envisagesconstructions of which the following gives examples.

BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Preferred forms of the present invention will now be describedwith reference to the accompanying drawings.

[0023]FIG. 1 is an illustration of a respiratory humidifier system thatmay be used with the nasal cannula assembly of the present invention.

[0024]FIG. 2 is a perspective view of a first form of the nasal cannulaassembly of the present invention.

[0025]FIG. 3 is an exploded perspective view of the first form of thenasal cannula assembly of FIG. 2, showing two parts making up the nasalcannula, a face mount part and gases flow manifold part attached totubing supplying gases to the patient.

[0026]FIG. 4 is a perspective view of a second form of the nasal cannulaassembly of the present invention, showing tubing providing a gasessupply to a gases flow manifold part and face mount part when inconnection.

[0027]FIG. 5 is a perspective view of the second form of the nasalcannula assembly of FIG. 4 where the gases flow manifold part isdisengaged from the face mount part.

[0028]FIG. 6 is a perspective view of the second form of the nasalcannula assembly of FIG. 4 where the gases flow manifold part isdisengaged from the face mount part, showing the manifold part can befitted to either side of the face mount part.

[0029]FIG. 7 is a back perspective view of the second form of the nasalcannula of FIG. 4, showing a removable breathable pad on the inner sideof the face mount part that abuts the patients face.

[0030]FIG. 8 is a perspective view of a third form of the nasal cannulaassembly of the present invention, particularly showing a gases flowmanifold part that allows for the attachment of removable prongs.

[0031]FIG. 9 is a perspective view of the third form of the nasalcannula assembly of the present invention, showing a strap andbreathable pad fittable to the manifold part of FIG. 8.

[0032]FIG. 10 is a perspective view of a first form of removable prongscapable of being attached to the manifold part of FIG. 8.

[0033]FIG. 11 is a perspective view of a second form of removable prongscapable of being attached to the manifold part of FIG. 8.

[0034]FIG. 12 is a perspective view of a patient wearing the nasalcannula assembly of FIG. 4, showing the use of a neck tie to take someweight of the tubing and a head strap assisting in the maintaining ofthe assembly to the patient's face.

[0035]FIG. 13 is a front view of a patient wearing a nasal cannulaassembly present invention where the assembly is held to the patient'sface with the assistance of ear loops.

[0036]FIG. 14 is a side view of the patient and nasal cannula assemblyof FIG. 13.

[0037]FIG. 15 is a perspective view of a tracheostomy fitting.

[0038]FIG. 16 is a front view of a patient with a tracheostomy andfitting attached to a breathing supply where a neck tie or lanyard isused to support the conduit supplying gases to the patient.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0039] Whether used in a hospital environment or in a home environment,the nasal cannula assembly of the present invention will generally haveassociated three main pieces of apparatus. Firstly an active humidifierthat controls the temperature of a heater plate heating a body of waterto achieve a desired temperature and humidity of the gases beinghumidified. Secondly a transport conduit from the humidifier to thepatient is also required, which is preferably heated to reducecondensation, or “rain out”. Thirdly a nasal cannula designed to fitinto the nasal cavity of a patient or user and deliver humidified,pressurized gases.

[0040] Referring to FIG. 1 a humidifying circuit as might be used withthe nasal cannula of the present invention is shown. A patient 1 isreceiving humidified and pressurised gases through a nasal cannula 20connected to a humidified gases transportation pathway or inspiratoryconduit 3 that in turn is connected to a humidifier 8 (includinghumidification chamber 5) that is supplied with gases from a blower 15or other appropriate gases supply means. The inspiratory conduit 3 isconnected to the outlet 4 of a humidification chamber 5 which contains avolume of water 6. Humidification chamber 5 is preferably formed from aplastics material and may have a highly heat conductive base (forexample an aluminium base) which is in direct contact with a heaterplate 7 of humidifier 8. The humidifier 8 is provided with control meansor electronic controller 9 which may comprise a microprocessor basedcontroller executing computer software commands stored in associatedmemory. Gases flowing through the inspiratory conduit 3 are passed tothe patient by way of the nasal cannula 20.

[0041] Controller 9 receives input from sources such as user input meansor dial 10 through which a user of the device may, for example, set apredetermined required value (preset value) of humidity or temperatureof the gases supplied to patient 1. In response to the user set humidityor temperature value input via dial 10 and other possible inputs such asinternal sensors that sense gases flow or temperature, or by parameterscalculated in the controller, controller 9 determines when (or to whatlevel) to energise heater plate 7 to heat the water 6 withinhumidification chamber 5. As the volume of water 6 within humidificationchamber 5 is heated, water vapour begins to fill the volume of thechamber above the water's surface and is passed out of thehumidification chamber 5 outlet 4 with the flow of gases (for exampleair) provided from a gases supply means or blower 15 which enters thechamber through inlet 16. It should be noted that it is possible toobtain the relationship between the humidity of the gases inhumidification chamber 5 and the temperature of the heater plate 7.Accordingly, it is possible to utilise the heater plate temperature inan algorithm or a look-up table to determine the humidity of the gases.

[0042] The blower 15 may be provided with a variable speed pump or fan 2which draws air or other gases through the blower inlet 17. The speed ofvariable speed pump or fan 2 may be controlled by a further controlmeans or electronic controller 18 (or alternatively the function of thiscontroller 18 could be carried out by the other controller 9) inresponse to inputs from controller 9 and a user set predeterminedrequired value (preset value) of pressure or fan speed via dial 19.

[0043] A heating element 11 may be provided within the conduit or tubing3 to help prevent condensation of the humidified gases within theconduit. Such condensation is due to the temperature of the walls of theconduit being close to the ambient temperature, (being the temperatureof the surrounding atmosphere) which is usually lower than thetemperature of the humidified gases within the conduit. The heaterelement is effectively replaces the energy lost from the gases throughconduction and convection during transit through the conduit. Thus theconduit heater element ensures the gases delivered are at an optimaltemperature and humidity.

[0044] Side Entry Nasal Cannula

[0045] The nasal cannula assembly of the present invention provides apatient with a patient interface suitable for the delivery of highairflow, high humidity gas flow to the patient's nasal cavity. Aparticular aspect of the nasal cannula of the present invention is thesuitability for long term therapy where the patient, for example, apatient suffering from Chronic Obstructive Pulmonary Disease (COPD),will wear the cannula for several hours per day over weeks, months andin some cases years. Therefore, for patient's to accept use of nasalcannula under these circumstances the cannula need to be unobtrusive,comfortable to wear, noise free, suitable for wearing while sleeping,easy to clean and have prongs that can generate Positive End ExpiryPressure (PEEP). The cannula of the present invention may also be usedfor other therapies such as for Continuous Positive Airway Pressure(CPAP) therapy and the like.

[0046] A first form of the nasal cannula assembly of the presentinvention is shown in FIGS. 2 and 3. This nasal cannula, generallyindicated as 20, comprises a face mount part 21 including a pair oftubular nasal prongs 22, 23 integrally molded with or removably attachedto the face mount part 21, and a gases flow manifold part 24 that isintegrally molded with or attached to tubing 3, such as that describedabove.

[0047] The face mount part 21 and prongs 22, 23 are preferably mouldedfrom silicone or other flexible material as is known is the art ofcannula construction. The gases flow manifold part 24 is preferably madefrom a hard plastics material, although it may be manufactured in othersuitable materials.

[0048] The face mount part 21 is preferably integrally molded with theprongs 22, 23 and is shaped to generally follow the contours of apatient's face around the upper lip area. The inner side (not shown) ofthe face mount part 21 may be provided with a breathable pad, to bedescribed below. The outer side 25 of the face mount part 21 has mouldedin it an elongated oval recess 26 and two oval recesses 27, 28 thatextend through the face mount part 21 and each meet the tubularpassageway's formed within each of the tubular prongs 22, 23.

[0049] The gases flow manifold part 24 is generally tubular in shapehaving a substantially circular inlet (not shown) on one side thatcurves around to an elongated oval outlet 29. The circular inletreceives the end of the conduit or tubing 3, so that gases are suppliedto the gases flow manifold part 24 and are able to flow through theinlet and out the outlet 29. The tubing 3 is preferably permanentlyfixed to the manifold part 24, but may be releasably attachable.

[0050] The outlet 29, being elongated and oval in shape, fits into theelongated recess 26 in a friction or snap fit engagement with themanifold 21, such that a substantial force is required to remove themanifold part 24 from the elongated recess 26. Further, as the facemount part 21 is flexible and the manifold part 24 made from a harderplastics material it is possible for the manifold part outlet 29 to beeasily pushed or forced into the elongated recess 26. When the manifoldpart 24 is engaged with the face mount part 21 and in use, gases flowfrom the tubing 3, through the gases flow manifold part 24 out itsoutlet 29, into each of the oval recesses 27, 28, into each of theprongs 22, 23 and into the patient's nares.

[0051] The face mount part elongate recess 26 and manifold part outlet29 are symmetrical in shape and configuration and therefore the manifoldpart 24 is capable of being switched or flipped such that the tubing 3extends from either the left or right side of the patient's nares. Thismeans that the nasal cannula assembly 20 and associated tubing 3 arerelatively unobtrusive as the cannula 20 only requires a singlehorizontal side entry, not two entries as that of the prior art.

[0052] The nasal cannula assembly of the present invention is morecomfortable to wear as it sits under the septum of the nose and supportsthe two nasal prongs. As the prongs are made in one moulding of a softmaterial such as silicone the prongs are easy to insert in the patient'snares and comfortable to the patient.

[0053] For a nasal cannula assembly to be suitable for wearing duringsleep each night the cannula must be noise free. Many prior art cannulasare prone to whistling. With a range of airflows generally being between0 to 40 litres per minute, although airflows of 60 litres per minute areenvisaged for the present nasal cannula, and with the air or gases beingsupplied to a single horizontal entry point it has proved difficult toprevent whistling. For this reason the face mount part 21 is contouredsuch that the pressure distribution within the face mount part 21 forceseven airflows up each nasal prong.

[0054] As the nasal cannula assembly of the present invention is likelyto be used while a patient is sleeping, the cannula must be easilytailored for the patients sleeping arrangement. The cannula of thepresent invention supplies high flow humidified gases to the patientfrom either the left side or the right side of the cannula thus allowingthe minimum length connection circuit to the bedside unit supplying thehumidified gas. As the nasal cannula assembly of the present inventionallows for the horizontal entry of gases from either side the patientcan configure the unit as left or right entry for their particularsleeping arrangement. It is envisaged that the tubing 3 is approximatelytwo meters in length to allow for added flexibility of the cannulaReference is now made to FIGS. 4 to 7 that show a second form of thenasal cannula assembly of the present invention. In this form the nasalcannula assembly 30 is of a substantially similar form to the first formdescribed above in relation to FIGS. 2 and 3, and has a face mount part32, a pair of nasal prongs 33, 34, gases flow manifold part 35 andtubing 3. The face mount part 32 and pair of nasal prongs 33, 34 arepreferably integrally molded as one piece from a soft plastics materialsuch as silicone, although in other forms the face mount part and prongsmay be separate, but capable of attachment together for use.

[0055] The nasal prongs 33, 34 are tubular in shape and may beconsistent in diameter but may be shaped to fit the contours of thehuman nares.

[0056] A strap or strap attachment means 31 may be integrally formed orattached to the face mount part 32 in order to enable the nasal cannulaassembly 30 to be held in place about a patient's face.

[0057] The face mount part 32 has an open tubular recess 38 extendingbelow the nasal prongs 33, 34 that is capable of receiving a gases flowmanifold part 35 that is attached to or integrally formed with tubing 3.The tubular passageways within the nasal prongs 33, 34 extend throughthe face mount part and into the recess 38. The gases flow manifold part35 is blocked at one end 39 but attached to the tubing at the other endand has an elongate opening 37 that acts as an exit for gases receivedfrom the tubing 3. Due to the flexible nature of the material the facemount part 32 is made from, and as the gases flow manifold part 35 ismade from a hard plastics material, the gases flow manifold part 35 canbe pushed through the tubular recess 38 in the face mount part 32 andthe elongate opening 37 in the gases flow manifold part 35 meets withthe tubular passageways of the prongs 33, 34. Therefore, in use, gasesflowing through the tubing and into the gases flow manifold part 35 exitthrough the opening 37 and into the tubular passageways in the prongs33, 34, then into the patient's nares.

[0058] In order to assist with maintaining the gases flow manifold part35 within the manifold recess 38 the manifold part 35 is provided withan inner recessed portion 60 and contoured lip areas 58, 59. Whenengaged with the face mount part 32 the tubular body forming the recess38 sits within the inner recessed portion 60 and the edges of thetubular body abut the lips 58, 59 formed on the manifold part 35.

[0059] Breathable Pad

[0060] A breathable pad may be supplied with any of the nasal cannulaassemblies described above. In particular, such a pad 36 is shown inFIG. 7 in the second form of the nasal cannula assembly as describedabove. It must be appreciated that a pad of this type may be providedwith any of the other two forms as herein described.

[0061] The pad is preferably attached to the inside surface of the facemount part 32 that connects with the upper lip of the patient wearingthe cannula. The pad 36, which is preferably made from an absorbentcloth, reduces the incidence of heat and moisture on the patient's upperlip, where the face mount part 32 sits against their face.

[0062] The pad 36 is preferably attached to the face mount part 32 byadhesive, for example, the pad could be supplied with a sticky backingthat adheres to the face mount part, so that the pad can be easilyremoved from the face mount part and replaced as necessary.

[0063] The pad reduces the effects of heat against the patient's skinand improves hygiene, as any contaminants or cultures that may growclose to the patient's skin, in the warm environment can be removed onremoval and replacement of the pad.

[0064] Three Part Nasal Cannula

[0065] Referring now to FIGS. 8 to 11, a third font of the nasal cannulaassembly of the present invention is shown where the nasal cannulaassembly comprises three parts.

[0066] Firstly, a gases flow manifold part 40 is shown in FIG. 8 whichis designed for either left or right hand orientation and provides asymmetrical flow to a pair of nasal cannula assembly prongs 41, 42 (seeFIG. 10 or 11).

[0067] Next, a pair of soft nasal prongs 41 or 4) are provided that arecapable of being attached to the top of the gases flow manifold part 40allowing for a large range of different shaped and spaced prongs to beavailable to the patient. Two such configurations of prongs 41, 42 areshown in FIGS. 10 and 11. The prongs 41 of FIG. 10 are narrow elongatetubular members 43, 44 of a substantially constant diameter that arefittable into a patient's nares. The prongs are integrally molded with abody 45 that is fittable with the gases flow manifold part 40 (see FIG.8) by appropriate means, for example, friction or snap fit The prongs 42of FIG. 11 are tapered tubular members 46, 47 moulded to a body 48.Again, this body 48 is capable of being fitted (friction, snap or other)to the gases flow manifold part of FIG. 8. These prongs are preferablymade from a soft plastics material such as silicon, although othersuitable materials may be used.

[0068] With the prongs being removable they are easily cleaned and couldalso be disinfected for second or subsequent use.

[0069] The third part to the third form of the nasal cannula assemblyshown in FIGS. 8 to 11 is the face mount part 49 of FIG. 9. The facemount part 49 comprises a head strap 53 attached to a pad 50, that maybe a moulded or shaped substantially rigid pad, for example, made from aplastics material such as polypropylene. The pad 36 may include abreathable cloth pad on its surface that abuts a patient's face, similarto that pad 36 described in relation to FIG. 7, or the head straps 53may extend to sit behind the pad. The head strap 53 is preferably madefrom a flexible material, such as neoprene.

[0070] The plastic pad 50 is shown in FIG. 9 and has a plurality ofapertures 61 formed into to allow for heat and moisture to dissipatefrom the patient's facial surface. The pad 50 has fastening means 51, 52for holding the gases flow manifold part 49 in the correct position onthe upper lip of the patient. The fastening means may be clips 51, 52that are fittable into complimentary recesses 54, 55, 56, 57 provided inor on the manifold part 40 (see FIG. 8), but other appropriate fasteningmeans may be provided with the cannula. An example of other fasteningmeans is a loop that is integrally moulded as part of the prongs whichwraps around the face mount part and latches over a protrusion on themanifold part thus encapsulating the face mount part and holding theassembly together stably and securely. Another example of a fasteningmeans is a plastic Velcro™ type attachment where one side would attachto one side of the manifold part 40 and the other side to the plasticpad 50. For the fastening means shown in FIGS. 8 and 9 at least onerecess must be provided on either side of the manifold 40. In thepreferred form of the nasal cannula assembly two recesses 54, 55 areprovided on one side of the manifold 40 and two other recesses 56, 57 onthe other side of the manifold 40.

[0071] The attachment between the face mount part 49 and the manifoldpart 40 allows for either left or right hand orientation of the manifoldpart and associated tubing.

[0072] It is envisaged the cannula of the present invention will bereusable for several wearings on a single patient and as such the nasalcannula assembly must be hygienic. It is envisaged that all theembodiments of the nasal cannula assembly of the present invention asherein described can be disassembled so that the cannula is easier toclean. The prongs and integrally attached parts are capable of beingstored in a sterile solution until reused, much like false teeth arecurrently stored while not in use.

[0073] With a single flow entry cannula there will be less condensatedue to the reduction in surface area for heat loss and thus the cannulaof the present invention reduces the effects of condensation building inthe tubing and cannula.

[0074] The detachable nasal cannula assembly described in relation toFIGS. 8 to 11 allows a patient on long-term therapy to order theirparticular prong size but maintain a common tubing connection systemright to the point of connection into the manifold under the nose.

[0075] In other forms of the nasal cannula assembly of the presentinvention the assembly may only be provided with one nasal prongfittable into only one of the patient's nares. The purpose of such anassembly with one prong is to allow for consecutive use of a nasogastrictube. Nasogastric tubes are generally inserted in one of a patient'snares and extend down into their stomach. For example, it may benecessary or ideal for a patient to be fed by way of a nasogastric tubeand to also receive heated humidified gases. The nasal cannula assemblyof the present invention having only one prong would allow this.

[0076] Flexible Extension Dry Tube

[0077] Often an unheated flexible section of tubing is placed proximalto the patient to reduce torsion or pulling on the patient interface andreduce possible heat problems or over heating close to the patient. Inorder to reduce condensate forming in the unheated tubing, tubing can beprovided that has vapour transmission properties. Referring now to FIG.12 the nasal cannula of the present invention (in particular, that ofthe second form described herein) may be provided with a short piece ofbreathable tubing 62 between the nasal cannula 30 and heated tubing 3.The tubing 62 is preferably made from a material that allows fortransmission of water, such as a hydrophilic material, for exampleSYMPATEX™.

[0078] Test results show the performance of a 420 mm length ofbreathable tube, operating with air input at an absolute humidity of42.2 mg/L, an airflow of 10 litres per minute, in a room with ambientair at 22 degrees C. and 50% RH, only lowered the air temperature to 37and the absolute humidity to 41.15 mg/L at the exit of the dry tube. Incomparison a 420 mm length of non-breathable but insulated polyethylenetube under exactly the same conditions also output air at 41.15 mg/L. Inthe breathable tube there was significantly less condensate measured,therefore, some of the humidity that would otherwise be lost ascondensate on the wall is being transmitted through the breathable wall.

[0079] The result of providing the short section of breathable tubing 62is that a majority of humidity in the gases is transported to thepatient, and there is an insignificant and immeasurable loss of humiditythrough the breathable wall of the short tube 62, while condensate isreduced. The design of the high airflow high humidity system has beenoptimized to deliver a breathable gas treatment to patients attemperatures approximating body temperature and fully saturated withwater vapour for long treatment periods. The use of an unheatedbreathable conduit proximal to the patient to provide a connection thatis highly flexible and avoids condensation by breathing would beexpected to lower the humidity of the gas treatment thereby decreasingthe efficacy of the treatment. These results are surprising and arecounterintuitive and go some way to explaining why the use of abreathable tube as a short section of tubing before the patient has beenoverlooked. This short tube 62 is envisaged to be used with any tubedelivering heated and humidified gases to a patient.

[0080] Neck Tie

[0081] A neck tie or lanyard may be provided with the nasal cannulaassembly of the present invention. FIG. 12 shows such a tie 63. The tie63 is preferably connected to the tubing 3 or connection 67 between thetubing 3 and breathable tube 62. A toggle 64 is preferably provided withthe neck tie 63 in order to adjust the neck tie's length. The neck tiehas the purpose of taking some of the weight of the tubing 3 andprevents the weight of the tubing 3 pulling on the nasal cannulaassembly 30. This helps to prevent the prongs interfering with the verysensitive lining of the nasal passages. The loose fitting neck tie alsoprovides a convenient way of connecting the tubing 3 to the patientoutside the blankets. This allows the patient to turn in the bed andavoids the tubing 3 overheating if placed under the blankets.

[0082] The tie or lanyard described may be used with any breathingapparatus that supplies gases to a patient; for example it may be usedwith a nasal or face mask or with a tracheostomy fitting or connector.When the tie or lanyard is used with such apparatus it takes the weightof the conduit(s) or tubing supplying gases to the mask, connector orcannulae and helps reduce the pull on the mask, connector or cannulae.

[0083]FIGS. 15 and 16 show a tracheostomy fitting or connector that mayutilise a neck tie or lanyard of the present invention. The tracheostomyconnector 69 attaches to a tracheostomy mount 72 that extends into atracheostomy tube (not shown) through hole in a patient's 68 neck andinto their airway passages. The connector 69 provides a direct couplingof a tracheostomy tube to the breathing supply of gases received througha conduit 71. Preferably the conduit 71 is constructed in a breathablematerial, similar to that described above, but may be a heated tube.

[0084] The connector 69 has the conduit 71 attached directly to it andalso includes an expiratory port 70 to allow for expiration of gases. Oninspiration no gases flow occurs out the port 70 due to the flow ofgases to the connector 69 being greater than a patient's peakinspiratory flow. Therefore, there is also no or very little entrainingof gases from the ambient air.

[0085] Excess weight on the tracheostomy tube may cause excess movementof the tube, with the risk of complications such as displacement orrecannulation of the tracheostomy, the formation of granulation tissueor more seriously, stomal erosion. To obviate or reduce these problems atie or lanyard 73 can be connected to the conduit 71 or additionalconnector 74 (that may for example connector the conduit 71 to anadditional conduit 75 that supplies gases). The tie or lanyard 73transfers the weight of the conduits 71, 75 and connector 74 from thetracheostomy tube or mount 72 and distributes it onto the neck of thepatient leaving a minimal load directly on the tracheostomy tube ormount 72. Preferably the tie or lanyard 73 is adjustable so that the tieor lanyard length can be altered to suit a patient's requirements.

[0086] Ear Loops

[0087] Orientation of a nasal cannula is an essential requirement topatient comfort. If the nasal cannular is not held firmly in position,it can skew, placing unwanted load on the inside surfaces of thepatient's nares. However, to overcome this head gear is often providedwith nasal cannula, although, if the head gear is not tight the nasalcannula can still move. This type of tight tension can then compromisepatient comfort with pressure on the head and face, while forcing thecannula further up the patient's nose. Ideally nasal cannula shouldattach to the patient's face in a rigid manner, yet with low loading onthe head and face.

[0088] Referring to FIGS. 13 and 14 nasal cannula attachment means maybe provided to hold the nasal cannula assembly 30 to the patient's face.The attachment means are preferably ear loops 65, 66 that are connectedto the straps 31 of the face mount part 32 of the nasal cannula assembly30.

[0089] The loops 65, 66 extend from the face mount part 32 around thepatient's cars, and provide rigid anchoring when an inelastic materialis used. The loops 65, 66 are preferably made from a thin, round cordwith the ends captured in plastic, and are preferably adjustable. Theplastic ends of the loops 65, 66 are inserted into purpose made cavitiesin the straps 31, enabling adjustment of length for a comfortable, yetfirm fit.

[0090] In use, to fit the nasal cannula assembly, a first loop (forexample, loop 65) is placed over one ear, the nasal cannula assemblypositioned on the patient's face and in their nose, then the other earis passed through the second loop (for example, loop 66), so both loopssit snugly behind the ears. This method of fitting the nasal cannulaavoids the initial discomfort of gases being blown into the patient'seyes when the cannula assembly is pulled down the face for fitting withother headgear. Fastening the nasal cannula in this method provides anattachment means that is horizontally secure with minimum tensionapplied to the ear connection loops. The ear loops have the addedadvantage for a patient lying on their back that there are no strapsbehind the back of the head that are moved by head movement on thepillow.

We claim:
 1. A nasal cannula assembly adapted to deliver gases to a patient by way of a gases transport means comprising: a face mount part, including at least one nasal prong capable of being fitted into at least one of said patient's nares, a removable gases flow manifold part in use in fluid communication with said face mount part, said manifold part having a single horizontal side gases entry, in use, in fluid communication with said transport means.
 2. A nasal cannula assembly according to claim 1 wherein said gases flow manifold part is capable of being fitted with said face mount part in two configurations, a first configuration where said transport means extends to the left of said nasal cannula assembly and a second configuration where said transport means extends to the right of said nasal cannula assembly.
 3. A nasal cannula assembly according to claim 1 wherein said gases flow manifold part terminates at an open recess that in use is aligned with a complementary recess in said face mount part thereby providing gases flow to said at least one nasal prong and said at least one of said patient's nares.
 4. A nasal cannula assembly according to claim 1 wherein said face mount part and said at least one nasal prong are integrally moulded from a soft plastics material.
 5. A nasal cannula assembly according to any one of claims 1 to 3 wherein said at least one prong is detachable from said face mount part to allow different sized prongs to be placed on said face mount part to suit different sized patients.
 6. A nasal cannula assembly according to claim 1 wherein said nasal cannula assembly includes a breathable pad attached to the inner side of said face mount part, such that in use said pad abuts said patient's face in the upper lip region.
 7. A nasal cannula assembly according to claim 6 wherein said pad is removable from said face mount part.
 8. A nasal cannula assembly according to claim 1 wherein said nasal cannula assembly includes two nasal prongs.
 9. A nasal cannula assembly according to claim 1 wherein said nasal cannula assembly is attached to said gases transport means to transport gases by way of a breathable tube.
 10. A nasal cannula assembly according to claim 9 wherein said breathable tube is a short section of tubing constructed of a breathable or hydrophilic material.
 11. A nasal cannula assembly according to claim 1 wherein said nasal cannula assembly is attached to said patient with attachment means that loop about said patients' ears.
 12. A nasal cannula assembly according to claim 1 wherein said gases flow manifold part is made from a hard plastics material.
 13. A breathing assistance apparatus comprising: a pressurised source of gases, humidification means adapted to, in use, be in fluid communication with said source of gases and adapted to in use humidify said gases, humidified gases transport means adapted to, in use, be in fluid communication with said humidification means and adapted to in use convey said humidified gases, heating means disposed within said transport means and adapted to in use heat said gases as they pass through said transport means, and nasal cannula, adapted to deliver said humidified gases to said patient, said nasal cannula comprising a face mount part, including at least one nasal prong capable of being fitted into at least one of said patient's nares, a removable gases flow manifold part in use in fluid communication with said face mount part, said manifold part having a single horizontal side gases entry, in use, in fluid communication with said transport means.
 14. A breathing assistance apparatus according to claim 13 wherein said heating means comprises a heater wire disposed within, throughout or around said transport means.
 15. A breathing assistance apparatus according to claim 13 including a means for supporting the weight of said heated transport means including a loose fitting adjustable tie locatable about said patient's neck.
 16. A breathing assistance apparatus according to claim 13 wherein said gases flow manifold part is capable of being fitted with said face mount part in two configurations, a first configuration where said transport means extends to the left of said nasal cannula assembly and a second configuration where said transport means extends to the right of said nasal cannula assembly.
 17. A breathing assistance apparatus according to claim 13 wherein said face mount part and said at least one nasal prong are integrally moulded from a soft plastics material.
 18. A breathing assistance apparatus according according to claim 13 wherein said at least one prong is detachable from said face mount part to allow different sized prongs to be placed on said face mount part to suit different sized patients.
 19. A breathing assistance apparatus according to claim 13 wherein said nasal cannula assembly includes a breathable pad attached to the inner side of said face mount part, such that in use said pad abuts said patient's face in the upper lip region.
 20. A breathing assistance apparatus according to claim 13 wherein said nasal cannula assembly is attached to said gases transport means by way of a breathable tube.
 21. A breathing assistance apparatus according to claim 20 wherein said breathable tube is a short section of tubing constructed of a breathable or hydrophilic material.
 22. A breathing assistance apparatus according to claim 13 wherein said nasal cannula assembly is attached to said patient with attachment means that loop about said patients' ears.
 23. A breathing assistance apparatus according to claim 13 wherein said gases flow manifold part is made from a hard plastics material.
 24. A conduit support apparatus for a breathing assistance apparatus to supply gases to a patient by way of at least one conduit comprising: a tie or lanyard capable of being placed about said patient's neck, said tie or lanyard being connected to said at least one conduit such that said tie or lanyard supports the weight of said at least one conduit.
 25. A conduit support apparatus according to claim 24 wherein said breathing assistance apparatus is one of a mask, a nasal cannula assembly or a tracheostomy connector.
 26. A conduit support apparatus according to claim 24 wherein said breathing assistance apparatus comprises a nasal cannula assembly adapted to deliver gases to a patient comprising: a face mount part including at least one nasal prong capable of being fitted into at least one of said patient's nares, a removable gases flow manifold part in use in fluid communication with said face mount part, said manifold part having a single horizontal side gases entry, in use, in fluid communication with said transport means.
 27. A conduit support apparatus according to claim 24 wherein said conduit is at least partially a heated breathing tube. 